Manufacture of unsaturated hydrocarbons.



UNITED sT TEs PATENT came 7 FRANCIS EDWARD MATTHEWS, HENRY JAMES WHEELER BLISS, AND HARRY MONTAGU ELDER, OF LONDON, ENGLAND.

MANUFACTURE OF UNSATURATED HYDROCARBONS.

No Drawing.

To all whom it may concern:

Be it known that we, FRANoIs EDWARD MATTHEWS, of City road, London, England, HENRY JAMES WHEELERBLIss, of Ingram House, Stockwell, London, England,

and HARRY MoNT-AGU ELDER, of 28 Albemarle street, Piccadilly, London, England, all subjects of the King of Great Brltain, have invented new and useful Improvements in the Manufacture of Unsaturated Hydrocarbons,' of which the following is a specifiparing certain unsaturated hydroc'arbons,.

for example, the doubly unsaturated conjugated bodies.

We have now found that water, or steam, is a suitable agent for the preparation of unsaturated hydrocarbons from mono--, or di-, halids. steam, may, if desired, be combined with the action of catalytic substances. The temperature required varies within wide limits, according to the halid used, but it should be the temperature at which halogen acid is freely evolved, above that at which glycol (or unsaturated alcohol) is formed and should be kept below that at which any considerable decomposition of the product occurs.

One method of preparing glycols has been to treat dihalids with water-although it'is necessary in many cases to have lead ox1d,'or other basic oxid, or weak alkali,

' present to combine with the halogen acid evolved. It is also known that certain glycolsof the pinacone type break down fairly readily to form doubly unsaturated hydrocarbons, and it has recently been shown (in the specification of application for British Letters Patent No. 3873 A. D; 1912) that other glycols may also be treated so as to yield unsaturated hydrocarbons.

The action of the water, or

Specification of Letters Patent. Patented sept. 19, 1916. Application filed June. 2 8, 19 13. Serial No. 776,342.

example, phosphoric acid) which split off water from alcohols, or glycols, or those which split off halogen acid (for example,

the catalysts mentioned in Meyer &, J acobsen, Vol. 1 (1907) page 277 such as, cobalt chlorid, ferrous chlorid, lead chlorid,barium out this invention wechlorid, nickelchlorid, or copper chlorid, or the corresponding bromids, or certain other halogen compounds, particularly aluminium bromid; but the use of these, or any, catalysts is not as a rule required if a sufliciently elevated temperature be used.

The following are examples of how this invention" can be performed, but the invention is not limited to these examples.

Example 1: The mixed dichlorids obtained by chlorination of isoamyl chlorid in the manner described in the specification of the application for British Letters Patent No. 27 7 A. D. 1912, are distilled in steam in the usual manner-by passing steam through the liquid. The distillate contains a small proportion of isoprene.

Example 2: Instead of passing steam through the dichlorids mentioned in ex-' ample 1, a mixture of water and the dichlorid is boiled, or it may be heated in a sealed tube to 200 centigrade, or thereabout; in the latter case, however, a considerable proportion of the hydrocarbon formed is polymerized.

fExample 3: 2.3-dichlor-butane' is allowed to flow with, say, an equal volume of water into a vessel which :is maintained at a temperature of from about 600 to about 700 centigrade. Or the vapor of the dichlorid .maybe passedthrougha heated tube together with steam. The pro'duct is passed through a condenser in which the water and hydrochloric acid are condensed; if less than from two, to two and a half, parts of water to may be separated and again treated to coinplete the removal of hydrochloric acid in accordance with specification of British Patent 17234/12. Other di-halids of butane or of other hydrocarbons may be treated in a manner similar to that described in this example.

The temperatures specified in the foregoing examples are suitable for carrying out the invention, but we do not limit ourselves to these temperatures. In general the temperature suitable for a particular di-halid is adjusted during the preparation by raising it until hydrochloric acid is freely evolved, Which may be detected, for example by de- ,termining the acidity of the condensed water. The vessels or tubes may be made of a resistant material, for example silica.

We do not limit ourselves to any particular method of heating, which may be external, or internal, say by means of an electric resistance. I

What we claim is 1. A proce ss of making doubly unsaturated hydrocarbons, from dihalogen substitution derivatives of saturated aliphatic hydrocarbons which process comprises the step of heating the said derivatives with H O in a fluid condition to a temperature at Which halogen acid is freely evolved, which temperature is above, that at which the glycol corresponding to the dihalogen substitution product used would be dehydrated, but below that at which any considerable decomposition of the unsaturated hydrocarbon would take place.

2. A process of making doubly unsaturated hydrocarbons from dihalogen substitution derivatives of saturated aliphatic hydrocarbons, which process comprises the step of heating the said derivatives With 11 0 in a fluid condition to a temperature at which halogen acid is freely evolved, which temperature is above that at which the glycol corresponding to the dihalogen substitution product used would be dehydrated, but below that at'which any considerable decomposition of the unsaturated hydrocarbon would take place, in the presence of a catalyst capable of causing the splitting off of halogen acid.

masses 3. A process of making doubly unsatu rated hydrocarbons, which process comprises the step of heating dichlor substitution products of paralfin hydrocarbons with water, to a temperature not below 200 C.

4. A process of making butadiene by passing 2.3 dichlor-but'ane together withwater through a tube heated to a temperature of from about 600 C. to about 700 0., substantially as described.

5. A process of making doubly unsaturated hydrocarbons from dihalogen substitution derivatives of saturated aliphatic hydrocarbons, which process comprises the step of heating said derivatives with Water, to a temperature not below 200 0., but not above 7 00 C.

6. A process of making doubly unsaturated hydrocarbons from dihalogen substitution derivatives of saturated aliphatic hydrocarbons, which process comprises the.

step of heating said derivatives with water, to a temperature at which halogen acid is freely evolved, which temperature is above that at which the glycol corresponding to the dihalogen substitution product used would be dehydrated, but below that at which any considerable secondary decomposition takes place, in the presence of catalytic means capable of aiding in the splitting off of halogen acid from the dihalogen substitution product used, and capable of aiding in corresponding thereto.

7. The process of making unsaturated hydrocarbons which comprises the step of heating a dihalogen substitution derivative of an aliphatic hydrocarbon, said derivative containing the group the splitting ofi of water from the glycol 

